Project Summary/Abstract Gait dysfunction is one of the most common causes of mobility disability and restricted independence after stroke. Rehabilitation often aims to improve mobility by ?teaching? people with stroke new walking patterns. Accordingly, recent rehabilitation research has developed innovative ways to teach new walking patterns. But this is only one piece of the puzzle ? after the patient acquires the new pattern, it is critical that we understand how best to deliver therapy so that the improvement lasts over time. Here, we will develop a new approach that leverages two different motor learning mechanisms and non-invasive brain stimulation, to drive longer-lasting improvements in walking after stroke. Split-belt treadmill walking has shown considerable potential for improving certain features of walking after stroke; however, this approach is limited by the relatively short-lived effects of this adaptation-based therapy. Reinforcement learning forms new movement patterns slowly, but these new patterns are more durable and resistant to decay. In Aim 1, we strive to prolong the positive effects of split-belt treadmill walking by improving the transfer to over ground walking. We will use a split-belt treadmill to drive the patient to acquire the desired walking pattern and then reinforce the improved pattern over ground using real-time biofeedback. In Aim 2, we will fortify the effect of this reinforcing feedback using non-invasive brain stimulation to facilitate even longer-lasting learning. The findings of this proposal will make two considerable contributions to gait rehabilitation after stroke: we will 1) offer a new approach where multiple motor learning mechanisms are used in combination to drive long-lasting improvements in walking after stroke, and 2) develop a new protocol for using non-invasive brain stimulation that can be applied easily in the clinic to extend the positive effects of post-stroke gait rehabilitation. These findings will also have broader impact by revealing how multiple motor learning mechanisms work together to drive changes in movement and how non-invasive brain stimulation can influence motor learning.